Today: only flights still to leave (it’s 2:09 pm at Chicago); 2 already left

Sunday, October 4 · our forecast odds · issued Sun 1:00 PM ET · connections flying that day

Today looks rough: weather pushes the legs’ average chance of arriving 15+ min late to 44% (calm day: 33%). Best bet: Southwest via Las Vegas, leaving 16:10, 39% on time.

Nonstops today


WN 2199 Southwest	MDW 21:30	SFO 00:10	35%	7%	0.1%	no record

Best connections today, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach San Francisco on time, from each leg’s forecast for the day. Total trip = scheduled departure to arrival (San Francisco is 2 h behind Chicago). Layovers up to 4 hours. Pick a connection for its 12-month details.


Delta Details →	MDW 17:10 → ATL 20:22DL 1728	2h 18m Atlanta	ATL 22:40 → SFO 00:36 +1DL 656	9h 26m	92%	59%
Southwest Details →	MDW 18:30 → PHX 20:10WN 2862	2h 10m Phoenix	PHX 22:20 → SFO 00:30 +1WN 2240	8h 00m	94%	58%
Southwest Details →	MDW 16:10 → LAS 18:00WN 2795	1h 50m Las Vegas	LAS 19:50 → SFO 21:30WN 2416	7h 20m	89%	39%
Southwest Details →	MDW 15:25 → DEN 17:00WN 2769	1h 35m Denver	DEN 18:35 → SFO 20:19WN 1773	6h 54m	82%	36%
Tight connection: often missed
Delta Details →	MDW 19:06 → MSP 20:51DL 4713 · flown by Endeavor	49m Minneapolis	MSP 21:40 → SFO 23:46DL 2089	6h 40m	52%	37%
Southwest Details →	MDW 18:30 → LAX 20:50WN 188	55m Los Angeles	LAX 21:45 → SFO 23:15WN 2429	6h 45m	55%	29%

How these are worked out. Each flight’s odds are our forecast for that day; flights of airlines we don’t forecast yet use their 12-month record and are marked. Makes the connection: the first flight’s 12-month lateness curve, scaled so its chance of arriving 15+ min late matches the day’s forecast, at the layover minus the 45-minute minimum (90 on separate tickets). Arrives on time: first flight not cancelled × connection made × second flight not cancelled × second flight within 15 minutes, each from the day’s forecast.

About this data: forecast odds from our model for Sun, Oct 4 (newest published update); 12-month records from US DOT on-time data, Aug 2025 – Jul 2026, all US airlines; regional flights count under the airline that sells them. JSON